Dynamic Compression-Bending Performance of Concrete-Filled Steel Tubular Columns under Lateral Impact

In this paper, a finite element model of concrete-filled steel tubular (CFST) columns under compression and lateral impact is developed and validated against previous experiments. After analyzing the influence of axial compression on the impact performance of CFST columns, the effects of eccentricity, material strength, and steel ratio on the dynamic compression-bending performances of CFST columns subjected to lateral impact are discussed. The simulated results show that at different axial compression ratios, CFST columns show overall bending failure under lateral impact. The axial force ratio below 0.2 shows a positive effect on the impact resistance of CFST columns, otherwise the axial force would degrade the impact resistance of CFST columns. Eccentricity has a negative effect on the dynamic compression-bending performance of CFST columns. The increase in the concrete strength has little effect on the dynamic compression-bending performance of the CFST columns under lateral impact and eccentric compression. The increases in steel strength and steel ratio can improve the dynamic compression-bending performances of the CFST columns under lateral impact and eccentric compression. Even though the prediction formula for the dynamic compression-bending performance of CFST columns shows good fitness with the simulated results, it is modified to have sufficient strength reserves for design applications.